NEC uPD78P078 - Manual (Page 177)

177
CHAPTER 7 CLOCK GENERATOR
Figure 7-9. Main System Clock Stop Function (2/2)
(c) Operation when CSS is set after setting MCC with main system clock operation
7.5.2 Subsystem clock operations
When operated with the subsystem clock (with bit 5 (CLS) of the processor clock control register (PCC) set to 1),
the following operations are carried out.
(a) The minimum instruction execution time remains constant (122
µ
s when operated at 32.768 kHz) irrespective
of bits 0 to 2 (PCC0 to PCC2) of the PCC.
(b) Watchdog timer counting stops.
Caution Do not execute the STOP instruction while the subsystem clock is in operation.
MCC
CSS
CLS
Main System Clock Oscillation
Subsystem Clock Oscillation
CPU Clock